Soil Fertility

Production Practices

Soil Fertility

Soil Fertility and Nutrient Management

Soil fertility explains the soil’s ability to supply plants essential nutrients (PEN). Nutrient Management is the practice of applying commercial and organic sources of plant essential nutrients to the soil. There are 16 PEN which are divided into four categories. To be considered a PEN the nutrient must fulfill one of two criteria: 1) in its absence the plant is unable to complete a normal life cycle or 2) the element plays a role in the plant metabolism. Finally PENs cannot be replaced by another element. For example, correcting a Nitrogen deficiency by adding Sodium nor are elements that only impact soil properties, i.e lime or organic matter, considered plant essential. The only method of knowing the nutrient need of the crop is through soil testing.

Oklahoma Soil Fertility and Nutrient Management Facts

The most limiting nutrient in Oklahoma crop production is N.

For every 1 percent OM there is approximately 1000 lbs of N.

Each year 1-2 percent of the OM breaks down releasing nutrients.

Banding P and K is the most efficient method of application.

In most crops split application of N is the best management practice.

Nitrogen use efficiency in cereal crops is about 33 percent.

Availability of all nutrients is impacted by soil pH.

Some nutrients are supplied to some degree through rainfall and irrigation (N, S, Cl)

Applied P is only available for 1 to 1.5 yrs. (exception Large P additions or Alfalfa)